Unhappy Customer

I bought an item at Legit Highveld Mall a day before lockdown 25 March 2020, I then realized that the item is small during lockdown. I then went to exchange at Legit Saveways, where they told me I need to exchange at Highveld. I then went to Highveld to where they told me I need to add money due to item was bought at half price and now full price.

I don’t understand why I should add,